DESCRIPTION: The purpose of the proposed research is to establish the aspects of ethnicity that are associated with the differential expression of cardiovascular disease processes in African Americans and Caucasian Americans. Given increasing awareness of the extent to which environments typically faced by these ethnic groups differ, environmental influence on these processes may be an important factor that is an aspect of ethnicity. Socioeconomic status (SES) is a useful index of such environments and is associated with cardiovascular disease (CVD). Since behavior is one pathway through which SES influences are thought to be expressed in disease, this proposal focuses specifically on stress responsivity, which is thought to be linked to the pathophysiology of CVD. Since such disease has its antecedents in childhood, a multiethnic pediatric sample will be employed. In addition, the subject sample will consist of twins. Investigation of the impact of environments on the expression of CVD can be achieved only with proper control for biological influences. Four hundred and eighty twin pairs will visit the laboratory. Half of the pairs will be Africa American, and half Caucasian American; and male and females will be equally represented. Subjects will complete three laboratory stressors: a video game task, a structured social interview, and the cold pressor. Stress responsivity will be assessed, with particular interest being paid to systemic vascular resistance (SVR). Left ventricular mass (LVM) will also be assessed. Sophisticated environmentally and genetically informative analyses will permit quantification of environmental impact upon SVR responsivity and LVM. It is hypothesized that environmental influences (SES) will account for a greater proportion of the variance in SVR responsivity and LVM in African Americans than Caucasian Americans. The hypothesis that SVR responsivity is a pathway through which SES exerts its influence on LVM will also be tested. The long-term objectives are to provide a better understanding of environmental influences on CVD which will aid in the development of improved primary prevention programs.